title: Intravaginal cytomegalovirus (CMV) challenge elicits maternal viremia and results in congenital transmission in a guinea pig model.
abstract: BACKGROUND
  The objective of this study was to compare intravaginal (ivg) and subcutaneous (sc) administration of the guinea pig cytomegalovirus (GPCMV) in pregnant and non-pregnant guinea pigs. These studies tested the hypotheses that ivg infection would elicit immune responses, produce maternal viremia, and lead to vertical transmission, with an efficiency similar to the traditionally employed sc route.
  
  
  RESULTS
  Four groups of age- and size-matched guinea pigs were studied. Two groups were pregnant, and two groups were not pregnant. Animals received 5 x 10(5) plaque-forming units (PFU) of a GPCMV reconstituted from an infectious bacterial artificial chromosome (BAC) construct containing the full-length GPCMV genome. Seroconversion was compared by IgG ELISA, and viremia (DNAemia) was monitored by PCR. In both pregnant and non-pregnant animals, sc inoculation resulted in significantly higher serum ELISA titers than ivg inoculation at 8 and 12 weeks post-infection. Patterns of viremia (DNAemia) were similar in animals inoculated by either sc or ivg route. However, in pregnant guinea pigs, animals inoculated by both routes experienced an earlier onset of DNAemia than did non-pregnant animals. Neither the percentage of dead pups nor the percentage of GPCMV positive placentas differed by inoculation route.
  
  
  CONCLUSIONS
  In the guinea pig model of congenital CMV infection, the ivg route is as efficient at causing congenital infection as the conventional but non-physiologic sc route. This finding could facilitate future experimental evaluation of vaccines and antiviral interventions in this highly relevant animal model.
authors.affiliation: Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota Medical School, 2001 6th Street SE, Minneapolis, MN 55455, USA.
authors.forename: Megan J
authors.initials: MJ
authors.lastname: Olejniczak
authors.forename: K Yeon
authors.initials: KY
authors.lastname: Choi
authors.forename: Michael A
authors.initials: MA
authors.lastname: McVoy
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Cui
authors.forename: Mark R
authors.initials: MR
authors.lastname: Schleiss
mesh_terms: D000818:Animals; D002460:Cell Line; D003587:Cytomegalovirus / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D003586:Cytomegalovirus Infections / Q000635:transmission* / Q000821:virology; D004195:Disease Models, Animal; D005260:Female; D006168:Guinea Pigs; D006801:Humans; D018445:Infectious Disease Transmission, Vertical; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000821:virology*; D014621:Vagina / Q000821:virology*; D014766:Viremia / Q000635:transmission* / Q000821:virology